Digital Commons Network^™

Road Rescue Implements A Continuous Process Improvement Framework, John Olson, Paul Savory

John Olson

Continuous improvement programs traditionally focus on making small incremental improvements to a system. Unfortunately, their success can be limited due to the rapid changing environment within which most small companies operate. Improvement efforts should be flexible enough to capitalize on incremental and radical changes to a system. This paper presents a case analysis of how Road Rescue, an ambulance manufacturer, uses a continuous improvement framework to capitalize on both radical and incremental improvement opportunities. Results include a 10% increase in throughput, reduced cycle time of 44%, increased customer satisfaction, and higher quality.

Modelling And Simulation Of The Magnetically Impelled Arc Butt (Miab) Process For Transmission Pipeline Applications, John Norrish, Dominic Cuiuri, Mohammad Hossain

Dominic Cuiuri

Early patents for the Magnetically Impelled Arc Butt process (MIAB) date back to 1940 [1] and the basic principles of the process have remained unchanged from this time. The process was however refined in the 1970s for use in the production of automotive components and has been used extensively in this area. Investigation of the process for pipe girth welding have been reported and commercial pipe welding heads are reported to be available in the Ukraine [2], Although the process is well established it is believed that a more fundamental analysis of the mechanisms involved would assist in the optimisation …

Patient-Centered Appointment Scheduling Using Agent-Based Simulation, Tammy Toscos, Ayten Turkcan, Brad Doebbeling

Tammy R Toscos

Enhanced access and continuity are key components of patient-centered care. Existing studies show that several interventions such as providing same day appointments, walk-in services, after-hours care, and group appointments, have been used to redesign the healthcare systems for improved access to primary care. However, an intervention focusing on a single component of care delivery (i.e. improving access to acute care) might have a negative impact other components of the system (i.e. reduced continuity of care for chronic patients). Therefore, primary care clinics should consider implementing multiple interventions tailored for their patient population needs. We collected rapid ethnography and observations to …

Failure Simulations At Multiple Length Scales In High Temperature Structural Alloys, Chao Pu

Doctoral Dissertations

A number of computational methodologies have been developed to investigate the deformation and damage mechanism of various structural materials at different length scale and under extreme loading conditions, and also to provide insights in the development of high-performance materials.

In microscopic material behavior and failure modes, polycrystalline metals of interest include heterogeneous deformation field due to crystalline anisotropy, inter/intra grain or phase and grain boundary interactions. Crystal plasticity model is utilized to simulate microstructure based polycrystalline materials, and micro-deformation information, such as lattice strain evolution, can be captured based on crystal plasticity finite element modeling (CPFEM) in ABAQUS. The comparison …

Modeling Of Gas Production From Shale Reservoirs Considering Multiple Transport Mechanisms, Chaohua Guo, Mingzhen Wei, Hong Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when …

A Robust Data Exchange Framework For Connected Vehicle Technology Supported Dynamic Transit Operations, Yucheng An

All Theses

Transit systems are an integral part of surface transportation systems. A connected vehicle technology (CVT) supported transit system will assist the users to manage trips both dynamically and efficiently. The primary focus of this research is to develop and evaluate the performance of a secure, scalable, and resilient data exchange framework. In the developed data exchange framework, a new data analytics layer, named Transit Cloud, is used to receive data from different sources, and send it to different users for a Dynamic Transit Operations (DTO) application. The DTO application allows the transit users to request trip information and obtain itineraries, …

Open Source Toolkit For Reentry Object Modeling, Christopher Lloyd Ostrom Ii

Master's Theses

Predicting the mass, position, and velocity of an object during its reentry are critical to satisfy NASA and ESA requirements. This thesis outlines a 3-D orbit and mass determination system for use on low earth orbit as applicable to general objects, of various material and size. The solution uses analytical models to calculate heat flux and aerodynamic drag, with some basic numerical models for simple orbit propagation and mass flow rate due to ablation. The system outlined in this thesis currently provides a framework for rough estimates of demise altitude and final mass, but also allows for many potential accuracy …

Spare Parts On Demand Using Additive Manufacturing : A Simulation Model For Cost Evaluation., Stefan Jedeck

Electronic Theses and Dissertations

Little is known about the impact of additive manufacturing in the spare part supply chain. A few studies are available, but they focus on specific parts and their applications only. A general model, which can be adapted to different applications, is nonexistent. This dissertation proposes a decision making framework that enables an interested practitioner/manager to decide whether using additive manufacturing to make spare parts on demand is economical when compared to conventional warehousing strategy. The framework consists of two major components: a general discrete event simulation model and a process of designing a wide range of simulation scenarios. The goal …

Heat Transfer Mechanisms In Water-Based Nanofluids., Masoudeh Ahmadi

Electronic Theses and Dissertations

Nanofluids are a class of heat transport fluids created by suspending nano-scaled metallic or nonmetallic particles into a base fluid. Some experimental investigations have revealed that the nanofluids have remarkably higher thermal conductivities than those of conventional pure fluids and are more suited for practical application than the existing techniques of heat transfer enhancement using millimeter and/or micrometer-sized particles in fluids. Use of nanoparticles reduces pressure drop, system wear, and overall mass of the system leading to a reduction in costs over existing enhancement techniques. In this work, the heat transfer coefficient is determined experimentally using copper oxide (CuO) based …

An Invastigation Of Band-Limited Fluid Damper Configuration Using Lumped Parameter Modeling, Ye Hong

Mechanical and Aerospace Engineering Theses

Vehicle suspension system is one of the key factors related to the vehicle dynamic characteristic. The fine tuning of suspension system between vehicle handling and ride comfort is not only a trade-off between these two aspects, but also, has its impact on vehicle safety and durability. For an optimal damper performance, the damper needs to generate sufficient damping force at maneuvering frequency (< 2 Hz); and it also needs to generate less damping force, which allow spring to filter the high frequency noise (> 2 Hz) generated by vehicle travels along rough road condition at speed. In order to achieve such performance, a lumped parameter model of Band-Limited Damper is proposed. Frequency response of both Conventional Damper and Band-Limited Damper are …

Numerical Simulations Of Twin Formation And Extension In Thin Face-Centred Cubic Metallic Films, Romuald Bejaud, Sandrine Brochard, Julien Durick

Nanomechanical Testing in Materials Research and Development V

The basic mechanisms of plasticity in face-centred cubic materials are now well known in bulk materials. However, several experimental studies have shown that at the nanoscale, some of its mechanisms can induce surprising mechanical properties when compared to bulk behaviour. The formation and extension of twins in metallic nanowire can, for example, generate super-plasticity [1] or the presence of growth nano-twins within a material can lead to strengthening effects [2]. Atomic simulations are particularly adapted for studying the plasticity mechanisms at play, since they allow their visualization at the atomic scale.

While many atomistic simulations studies have been focused on …

Water Resources Systems Analysis - University Of Texas San Antonio, Marcio Giacomoni

All ECSTATIC Materials

Systems Analysis methods use algorithmic and mathematical approaches for problem-solving. These are powerful methods that can be applied to solve complex design and management problems for water resources systems and other engineering areas. This class will focus on optimization methods, such as linear programming, integer programming, nonlinear programming, genetic algorithms, and dynamic programming, and their application to water resources systems. Advanced Systems Analysis methods, including sensitivity analysis, alternatives generation, and multi-objective optimization will be introduced to address the complexities associated with public sector decision-making. Course taught at University of Texas San Antonio.

Techno-Economic Analysis Of Protein Concentrate Produced By Flash Hydrolysis Of Microalgae, Alexander Nana Yaw Asiedu

Civil & Environmental Engineering Theses & Dissertations

Process simulation and techno-economic analysis of 95wt.% protein concentrate from microalgae has been performed using SuperPro Designer v. 9.0. This work, first of its kind, is focused on the economic analysis of protein concentrate that includes processes such as microalgae cultivation, harvesting, protein extraction and drying steps. A baseline capacity of 160 MT/day protein concentrate production on commercial basis has been analyzed. This throughput requires 336 MT/day dry algae (54 wt.% protein). The amount of carbon dioxide required to grow this quantum of algae is estimated to be 648 MT/day, which is produced from an in situ 21 MW power …

Geometric And Operational Improvements At Continuous Flow Intersections To Enhance Pedestrian Safety, Angela Coates, Ping Yi, Peng Liu, Xinlu Ma

Ping Yi

Traditional four-phase, four-legged intersections may operate inefficiently under high traffic demand. Innovative geometric design configurations for intersections allow more efficient traffic operations and can significantly increase vehicle throughput. Continuous flow intersections (CFIs), also referred to as displaced left-turn intersections, use an unconventional lane arrangement to maximize the vehicular throughput. This arrangement involves displacing left-turn lanes across opposing through traffic before reaching the main intersection. Such an alteration allows left-turning and through vehicles to proceed simultaneously, and both intersection capacity and delay are improved as a result. Numerous studies have validated these operational improvements, but pedestrian accommodation often is low because …

Simulation Modeling For Sustainability: A Review Of The Literature, Young B. Moon

Mechanical and Aerospace Engineering - All Scholarship

This article is a review of work published in various journals and conference proceedings on the topics of Simulation Modelling for Sustainability between January 2000 and May 2015. A total of 192 papers are reviewed. The article intends to serve three goals. First, it will be useful to researchers who wish to know what kinds of questions have been raised and how they have been addressed in the areas of simulation modelling for sustainability. Second, the article will be a useful resource for searching research topics. Third, it will serve as a comprehensive bibliography of the papers published during the …

Tropical Cyclone Wind Hazard Assessment For Southeast Part Of Coastal Region Of China, Sihan Li

Electronic Thesis and Dissertation Repository

Tropical cyclone (TC) or typhoon wind hazard and risk are significant for China. The return period value of the maximum typhoon wind speed is used to characterize the typhoon wind hazard and assign wind load in building design code. Since the historical surface observations of typhoon wind speed are often scarce and of short period, the typhoon wind hazard assessment is often carried out using the wind field model and TC track model. For a few major cities in the coastal region of mainland China, simple or approximated wind field models and a circular subregion method (CSM) have been used …

Guidelines For Scheduling In Primary Care: An Empirically Driven Mathematical Programming Approach, Hyun Jung Alvarez Oh

Doctoral Dissertations

Primary care practices play a vital role in healthcare delivery since they are the first point of contact for most patients, and provide health prevention, counseling, education, diagnosis and treatment. Practices, however, face a complex appointment scheduling problem because of the variety of patient conditions, the mix of appointment types, the uncertain service times with providers and non-provider staff (nurses/medical assistants), and no-show rates which all compound into a highly variable and unpredictable flow of patients. The end result is an imbalance between provider idle time and patient waiting time. To understand the realities of the scheduling problem we analyze …

Assessment Of Critical Technologies For Gas Turbine Engines Using Numerical Tools, Vinicius Pessoa Mapelli, Guillermo Paniagua, Jorge Sousa

The Summer Undergraduate Research Fellowship (SURF) Symposium

In 2014 gas turbine engine has reached a market value of 82.5 billion dollars, of which 59.5% are related to aircraft propulsion. The continuous market expansion attracts more and more the interest of researchers and industries towards the development of accurate numerical techniques to model thermodynamically the entire engine. This practice allows a performance and optimization analysis before the actual experimental testing, reducing the time and required investment in the design of a new engine. In this paper, a recently developed open source numerical tool named “Toolbox for the Modeling and Analysis of Thermodynamic Systems” (T-MATS) is used to assess …

Buckling-Driven Force Generation Of Cell Cortex, Pranith Lomada, Wonyeong Jung, Taeyoon Kim

The Summer Undergraduate Research Fellowship (SURF) Symposium

Actomyosin cortex, a thin network underlying cell membrane, is known to generate a large portion of tensile forces required for various cellular processes. Recently, theoretical studies predicted that buckling of actin filaments breaks symmetry between tensile and compressive forces developed by myosin motors, resulting in tensile stress at a network level. However, the significance of the filament buckling of the cortex has yet to be demonstrated either computationally or experimentally. Here, buckling-dependent stress generation of the cortex-like actomyosin network was investigated using an agent-based computational model consisting of actin filaments, actin cross-linking proteins (ACPs), and molecular motors. First, a wide …

Powder Compaction Simulation, Yuqi Fang, Caroline Baker, Marcial Gonzalez

The Summer Undergraduate Research Fellowship (SURF) Symposium

Powders are one of most manipulated materials in many industries such as food, pharmaceutical, energy and metallurgical industries. An important process for the powders is the compaction into solids with small porosity or high relative density. However, powders exhibit complex behavior during this process. After rearrangement and jamming of the powder bed, many types of deformation mechanisms dominate the compaction of granular materials, including elastic and plastic deformation of each individual particle. Therefore, having a better understanding of macroscale and microscale properties of powder beds and single particles during the compaction process is necessary. In addition, to reduce cost and …

Simulating Nanowires And Ultra-Thin Body Transistors Using Nemo5 On Nanohub.Org, Liang Yuan Dai, James E. Fonseca, Chu Yuan Chen, Gerhard Klimeck

The Summer Undergraduate Research Fellowship (SURF) Symposium

During the past twenty years, the most important aspects of semiconductor electronics have advanced into the nanometer range, resulting in exponential increases of microprocessor computing performance. As the size of electrical components continues to shrink, the cost of experimental research and industrial fabrication in this field has increased dramatically. Thus, the development of accurate nanoscale model simulations becomes necessary as a measure to decrease the high financial expenses of advancing semiconductor technology. This simulator supports atomistic modeling in order to provide an accurate description of the nanoscale devices, as current electrical components operate in the quantum regime and are affected …

Simulation Design For Photovoltaics Using Finite Difference Time Domain And Quadratic Complex Rational Function Methods, Jacob R. Duritsch, Haejun Chung, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

Photovoltaics (PV) can in principle supply enough renewable energy to offset a great deal of fossil fuel usage. To achieve this transition, it is critical to develop improved PV cells with decreased material costs and improved efficiencies. This goal can be greatly facilitated by a tool simulating the absorption and efficiency of experimentally relevant 3-D PV designs made of realistic materials, including those that have not yet been discovered. By incorporating the quadratic complex rational function algorithm (QCRF) with the finite difference time domain methods (FDTD), simulations can include frequency response and optical properties, while allowing full customization of tandem …

Electronic And Mechanical Material Properties From Dft Calculations, Usama Kamran, David Guzman, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Materials modeling provides a cost and time efficient method for studying their properties, especially in nanotechnology where length and time scales are not accessible experimentally. Our research focuses on developing a tool useful for both instructional and research purposes that calculates material properties. The tool relies on density functional theory (DFT) calculations to compute specific properties for a wide range of materials including semiconductors, insulators, and metals. A major goal with our tool was to keep the GUI very simple for novice users, such as students, while retaining an advanced option section for experienced users, such as researchers. The tool …

Thermal And Mechanical Properties Of Polymers Using Molecular Dynamics, Daniel Glass, Alejandro Strachan, Lorena Alzate-Vargas, Chunyu Li, Benjamin Haley

The Summer Undergraduate Research Fellowship (SURF) Symposium

Polymer systems have gained attention during the past years because of their technological and industrial applications. Simulations, particularly molecular dynamics, are very useful for exploring properties of amorphous polymers, without using experiments. Our goal is to create a readily-available tool that will perform MD simulations in order to get thermal and mechanical properties (Glass transition temperature, Young Modulus) of the polymers. The work that has been done will be part of a tool to help people to learn about polymer properties including Glass Transition Temperature. We model some polymers at a scale of 10,000 atoms. The tool uses LAMMPS to …

Multi-Barge Flotilla Impact Forces On Bridges, Peng Yuan, Issam Harik, Michael Davidson

Issam E. Harik

The current AASHTO equations for barge impact loads are based on scale models of barges, and may not accurately predict impact loads on bridge piers. The results of this study produce more realistic flotilla impact design loads, potentially leading to a reduction in construction costs of bridges over navigable waterways. The objectives of this study are: (1) To conduct theoretical finite element analysis on various types of flotillas impacting bridge piers. The flotillas and the respective barges will be of the type commonly traversing Kentucky’s waterways; and (2) To generate design equations for barge/flotilla impact loads. The study concludes the …

Equivalent Barge And Flotilla Impact Forces On Bridge Piers, Peng Yuan, Issam Harik

Issam E. Harik

Bridge piers located in navigable inland waterways are designed to resist impact forces from barges and flotillas in addition to other design considerations (e.g., scour, dead and live loads, etc.). The primary design tool for estimating these forces is the AASHTO Guide Specification which provides a simple hand calculation method for determining an “equivalent impact force”. The simplicity comes at a cost of excluding the effect of the pier shape, impact duration, and interaction between barges in a flotilla. The objective of this report is to present a hand calculation method for determining barge or flotilla equivalent static impact forces …

Thermodynamic And Kinetic Simulation Of Transient Liquid-Phase Bonding, Brad Allen Lindner

Theses and Dissertations

ABSTRACT

THERMODYNAMIC AND KINETIC SIMULATION OF TRANSIENT LIQUID-PHASE BONDING

by

Brad Lindner

The University of Wisconsin-Milwaukee, 2015

Under the Supervision of Professor Benjamin C. Church

The use of numeric computational methods for the simulation of materials systems is becoming more prevalent and an understanding of these tools may soon be a necessity for Materials Engineers and Scientists. The applicability of numerical simulation methods to transient liquid-phase (TLP) bonding is evaluated using a type 316L/MBF-51 material system. The comparisons involve the calculation of bulk diffusivities, tracking of interface positions during dissolution, widening, and isothermal solidification stages, as well as comparison of …

Fundamental Problems In Porous Materials: Experiments & Computer Simulation, Zhanping Xu

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Porous materials have attracted massive scientific and technological interest because of their extremely high surface-to-volume ratio, molecular tunability in construction, and surface-based applications. Through my PhD work, porous materials were engineered to meet the design in selective binding, self-healing, and energy damping. For example, crystalline MOFs with pore size spanning from a few angstroms to a couple of nanometers were chemically engineered to show 120 times more efficiency in binding of large molecules. In addition, we found building blocks released from those crystals can be further patched back through a healing process at ambient and low temperatures down to -56 …

Simulation And Validation Of Radio Frequency Heating Of Shell Eggs, Soon Kiat Lau

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Finite element models were developed with the purpose of finding an optimal radio frequency (RF) heating setup for pasteurizing shell eggs. Material properties of the yolk, albumen, and shell were measured and fitted into equations that were used as inputs for the model. When the egg was heated by itself, heating tend to be focused at the air cell to result in a “coagulation ring.” The focused heating near the air cell of the egg prevented satisfactory pasteurization of the egg, but deeper analysis of the simulation results offered a new perspective on how non-uniform RF heating could occur in …

Traction-Separation Relationships For Hydrogen-Induced Grain Boundary Embrittlement In Nickel Via Molecular Dynamics Simulations, Wesley Allen Barrows

Graduate Theses and Dissertations

The deleterious effects of atomic and molecular hydrogen on the mechanical properties of metals have long been observed. Although several theories exist describing the mechanisms by which hydrogen negatively influences the failure of materials, a consensus has yet to be reached regarding the exact mechanism or combination of mechanisms. Two mechanisms have gained support in explaining hydrogen’s degradative role in non-hydride forming metals: hydrogen-enhanced localized plasticity and hydrogen-enhanced decohesion. Yet, the interplay between these mechanisms and microstructure in metallic materials has not been explained. Accordingly, for this thesis, the three main objectives are: (i) to develop a numerical methodology to …